mcs/class/Mono.Security/Mono.Security.Cryptography/RC4.cs

   1 //
   2 // RC4.cs: RC4(tm) symmetric stream cipher
   3 //      RC4 is a trademark of RSA Security
   4 //
   5 // Author:
   6 //      Sebastien Pouliot (spouliot@motus.com)
   7 //
   8 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
   9 //
  10
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System;
  33 using System.Security.Cryptography;
  34
  35 namespace Mono.Security.Cryptography {
  36
  37 public abstract class RC4 : SymmetricAlgorithm {
  38
  39         private static KeySizes[] s_legalBlockSizes = {
  40                 new KeySizes (64, 64, 0)
  41         };
  42
  43         private static KeySizes[] s_legalKeySizes = {
  44                 new KeySizes (40, 2048, 8)
  45         };
  46
  47         public RC4()
  48         {
  49                 KeySizeValue = 128;
  50                 BlockSizeValue = 64;
  51                 FeedbackSizeValue = BlockSizeValue;
  52                 LegalBlockSizesValue = s_legalBlockSizes;
  53                 LegalKeySizesValue = s_legalKeySizes;
  54         }
  55
  56         new static public RC4 Create()
  57         {
  58                 return Create ("RC4");
  59         }
  60
  61         new static public RC4 Create (string algName)
  62         {
  63                 object o = CryptoConfig.CreateFromName (algName);
  64                 // in case machine.config isn't configured to use
  65                 // any RC4 implementation
  66                 if (o == null) {
  67                         o = new ARC4Managed ();
  68                 }
  69                 return (RC4) o;
  70         }
  71 }
  72
  73 }